The DRG Estrone ELISA is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of Estrone in serum and EDTA plasma.
There are three forms of estrogens in the female body: estrone (E1), estradiol (E2), and estriol (E3. The estrogens are involved in the development of female sex organs and secondary sex characteristics and effect most organ systems, including brain, breast, cardiovascular (heart and vasculature), immune, reproductive (ovaries and uterus), bladder, skin, and bone (1,11).
Estrone is produced primarily from androstenedione. In premenopausal women, more than 50% of the estrone is secreted by the ovary. In pre-pubertal children, men and postmenopausal women, the major portion of estrone is derived from peripheral tissue conversion (2). During the follicular phase of the menstrual cycle, the estrone level increases with a peak around day 14 and decreases thereafter. A second peak during the luteal phase occurs around day 21 of the cycle. These changes of estrone concentration mirror the estradiol levels (3). Up to week 4-6 of pregnancy, estrone originates primarily from maternal sources but gradually increases during week 6-10 of pregnancy due to placental secretion of estrone (4). After menopause, estrone levels do not decline as dramatically as estradiol levels. In postmenopausal women, estrone is the major estrogen. In males the concentration of E1 has been reported to increase with age inversely to that of 17-OH-progesterone (5,9).
In premenopausal women estrone levels can increase after conversion of large amounts of androstenedione produced in polycystic ovary syndrome (6) and ovarian tumors. Furthermore, excess weight results in increased estrogen concentrations from peripheral conversion of androgens to estrogens (mainly E1) in adipose tissue by aromatase enzyme (10).
This test can be used for monitoring low-dose female hormone replacement therapy in post-menopausal women, monitoring of anti-estrogen therapy (e.g. with aromatase inhibitors), and as an adjunct to clinical assessment, imaging studies and bone mineral density measurement in the fracture risk assessment of postmenopausal women. In addition, it can be useful as part of the diagnosis and work-up of precocious and delayed puberty in females (to a lesser degree in males), and of suspected disorders of sex steroid metabolism (e.g. aromatase deficiency and 17 alpha-hydroxylase deficiency).
The DRG Estrone ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA), based on the principle of competitive binding.
The microtiter wells are coated with a polyclonal rabbit antibody directed towards an antigenic site of the Estrone molecule. Endogenous Estrone of a patient sample competes with an estrone-horseradish peroxidase conjugate for binding to the coated antibody. After incubation the unbound conjugate is washed off.
The amount of bound peroxidase conjugate is inversely proportional to the concentration of Estrone in the sample. After addition of the substrate solution, the intensity of colour developed is inversely proportional to the concentration of Estrone in the patient sample.